Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
Laser speckle contrast imaging (“LSCI”) is a wide-field 2D imaging technique capable of rapid mapping dynamic blood flow within tissue beds in vivo. In LSCI, a digital camera may be used to record speckle patterns (i.e., coherent interference) formed by the coherent addition of scattered laser light propagating within tissue. The statistical properties of speckle pattern are dependent on the coherence of the incident light and the tissue optical properties. For a perfused tissue, the motion of red blood cells (“RBCs”), for example, may cause localized intensity fluctuations in the speckle pattern that may be analyzed with spatial, temporal, or combined spatiotemporal contrast algorithms to provide a dynamic blood perfusion map, indicating blood supply to the living tissue of interest.
LSCI is typically used for pre-clinical and clinical applications in the monitoring of, cerebral blood flow, and skin tissue perfusion during the wound healing, for example. LSCI is, however, traditionally married with a difficulty in visualizing small blood vessels. This poor visualization occurs even when the exposure time of the detector is long, because the technique may fail to account for scattering from static tissue elements.
An alternative visualization method is optical coherence tomography (“OCT”) that is a non-invasive method for providing high resolution (˜10 μm) and three-dimensional images of microstructures within biological tissues. Optical microangiography (“OMAG”) is a technique for processing an OCT dataset that allows extraction of three-dimensional microvasculature from the OCT images, with capillary resolution. OMAG has been used in a variety of applications which include tracking wounds and burns in mouse ear, imaging of the human corneo-scleral limbus and human retina, studies of mouse brain and others, but often suffers from background noise that arises from the stationary tissue background that may obscure the visualization and quantification of the capillary blood flows within tissue beds.